maxim



(No Model.)

- H. S. MAXIM. ELECTRIC LAMP.

No. 244,277. Patented July 12,1881.

INVENTOR:

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UNITED STATES PATENT OFFICE.

HIBAM S. MAXIM, OF BROOKLYN, ASSIGNOE, BY MESNE ASSIGNMENTS, TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NEW YORK, N. Y.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 244,277, dated July 12, 1881,

Application filed December 8, 1880. (No model.)

To all whom it may concern:

Be it known that I, HIRAM S. MAXIM, of the city of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Electric Lamps, of which the following is a specification, reference being had to the accompanying drawings, which form a part hereof.

My invention relates to the class of lamps known as incandescent lamps,in whichlight is produced by the incandescence of a continuous strip or conductor of low conductivity, forming a part of the electrical circuit of the lamp. Where carbon is used for such conductor it has been found necessary to eflectually protect the conductor from all access of air, as carbon readily oxidizes when highly heated. For this purpose the carbon conductor has usually been inclosed in a glass globe from which the air has been more or less perfectly exhausted or excluded, and various means have been devised for making perfectly-tight joints about the conducting-wires, such as stoppers of wood or other material sealed with gum or wax mercurial seals, and fusing the glass of the globe directly to conducting-wires of platinum. As is well known, only small platinum wires can be sealed into the glass in this way, as the contraction and expansion of the parts tend to crack the glass about the connections when wires of anyconsiderable size are used, and as the conductivity of platinum is comparatively low it has been found necessary to make the conductor of very high resistance, and to use a current of small quantity and high potential in lamps so constructed. Lamps of high resistance cannot well be used in any considerable number in series, on account of the immense electro-motive force required for passing the current through their combined resistances and it is one of the objects of my present invention to provide an incandescent lamp adapted to be used in series and capable of giving a large amount of light. I accomplish this by dividing the conducting-wires into several branches where they pass through the glass of the globe, and sealing the glass of the globe directly about these branches.

In the drawings, Figure 1 is a central vertical section of a lamp constructed in accordance with my invention; and Fig. 2 is a transverse section of the same, taken at the line X X in Fig. 1.

Similar letters of reference indicate like parts in each.

A is the carbon conductor, to be rendered incandescent by the passage of the current, and Bis a glass globe inclosing it. C O are the conducting-wires for conveying the current to the incandescentpart of the lamp. The globe 6c is made with a neck, D, for convenience of construction and for attachment to a suitable support. Each of the conducting-wires is divided into several branches, as shown at c c, and the glass is sealed by fusion to these branches. Care should be taken that the glass is thoroughly fused and united to all of the branches, so as to make a perfectly-tight joint. I prefer to make the branches where they pass through the glass of platinum, as that is the metal to which glass most perfectly adheres, and its coeffieieut of expansion is nearly the same as that of glass. The main parts of the conductingwires may be made of any suitable metal, preferably copper, on account of its high conductivity. The clamps, however, by means of whichthe carbon conductor is secured to the conducting-wires I prefer to make of platinum. The branches of the conducting-wires on each side are securely connected electrically with the main parts of the conducting-wires above and below the points where the glass is sealed to them.

The two main wires may be divided into any number of branches found desirable, and in this way very fine wires, and a large number of them, may be used at the points where the conducting-wires pass through the glass, and a current of considerable quantity may be used without fracturing the glass. 0

This construction is especially adapted to lamps in which conductors of comparatively low resistance are used; but it may be adopted with advantage in all lamps of this class. The air is exhausted or otherwise removed from the 9 5 globe in any convenient way.

Having thus described my invention, what two or more branches, to which the material I claim as new, and desire to secure by Letof the globe is directly sealed by fusion, sub- 10 ters Patent, is v sta-ntially as described.

In an electric lamp, a continuous incandescent conductor inclosed in a transparent vac- H. S. MAXIM. uum-globe, in combination with conductingl Vitnesses:

wires leading to said conductor, each of which HENRY HINE, is divided Where it passes into the globe into G. F. RILEY. 

